Etna , Sicily : gradual increase of the volcanic tremor amplitude.

Wed, May, 18, 16
Posted by : Georges VITTON

Etna update, 17 May 2016, 20:00 UTC

Since early April 2016, there has been a gradual resumption of summit eruptive activity at Etna, which initially consisted of increased gas emission mainly from the Northeast Crater (NEC) and from the vent that had opened on 25 November 2015 on the upper east flank of the New Southeast Crater (NSEC). This was accompanied by rather discontinuous and small emissions of ash; during the first half of May, these emissions from the NSEC also produced small anomalies visible in the images of the thermal monitoring camera at Monte Cagliato (EMCT). On 7 May, an increase in the volcanic tremor amplitude, whose source shifted toward the NSEC, was accompanied by the appearance of a source of infrasonic signals at the NSEC; however, the poor weather conditions allowed only to observe a modest emission of ash from the NSEC (25 November vent) and from the NEC.

During the night of 16 May, very weak and rare glows were observd at the 25 November vent of the NSEC, again accompanied by infrasound signals originating from the same vent. On the early morning of 17 May, the monitoring network of the INGV-Osservatorio Etneo (INGV-OE) recorded a gradual increase of the volcanic tremor amplitude, accompanied by infrasound signals coming from the NEC, and intense degassing with occasional, weak ash emissions from the same crater. INGV-OE staff present in the area of the Grotta del Gelo (on the upper north-northwestern flank) reported hearing explosion sounds probably coming from the NEC.